Wood has long been milled for use in fabricating structural or decorative components in building and construction applications. Wood, however, while structurally strong, useful and well adapted for use in many residential and commercial situations, presents deterioration problems under certain circumstances. Also, stronger woods are considerably denser than weaker woods, and as a result, tend to be very heavy. Yet, many construction applications benefit from the use of construction materials that minimize weight and maximize strength. Materials such as fiberglass or carbon fibers are available that are both stronger and lighter than hard woods. Although these materials combine superior strength with light weight, their cost can be prohibitive, making them useful only in high value situations and not cost effective in normal wood replacement type applications.
Consequently, using light weight yet sufficiently strong composite materials (such as those disclosed in U.S. patent application Ser. No. 09/706,590, now abandoned, which is hereby incorporated by reference) to manufacture construction units for building applications is desirable. Because manufacture of composite material construction units may be specialized so as to maximize certain desirable properties, such as softness, hardness, durability and other qualities, traditional means of anchoring and interconnecting such units, such as by perforation or boring with a nail, anchor and or screw, may not be appropriate and may unnecessarily damage the material. Such use of perforation and/or boring type fasteners may also be unsightly and the fasteners may, over time, protrude out from the planar surface of the resulting assembled structure. Therefore, systems of assembling, interconnecting and/or fastening discreet construction units, such as planks, panels and boards, made of composite materials, that will complement the composite material, and not split, warp or otherwise harm the units, are desirable
For instance, one particular application of composite materials is in the building of outdoor decks. For such applications, other fastening systems have been previously developed that deviate from the traditional nail, screw and other perforation or boring types of fastening. Steel straps, for instance, may be used to hold boards together from the underside. Such systems, however, are both cumbersome to install and to maintain. Other underside type fastening systems, such as those using tongue and groove type interconnections, may require heavily specialized design, manufacture, tooling and shaping, as well as specialized fabrication techniques, increasing the cost of the unit. This type of construction may also impede proper drainage of the surface area.
Other systems attempted include using biscuit cutters (e.g., tools that can impart a circular shaped groove in a decking board) to cut a circular shaped hole, depression or groove in the decking board over a support joist. These holes receive a circular fastener that is then fastened to the support joist (for instance, by a screw). Again, however, such holes and the screws used in them may be unsightly, and may eventually protrude over time.
What is needed is a system for assembling and interconnecting composite material construction units that complements the durability of the composite materials used and that also is sufficiently hidden from the casual viewer so as to not detract from the color and beauty of the finished structure.